This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A005510 M2842 #18 Jul 04 2019 15:47:46 %S A005510 3,10,31,101,311,962,3132,10202,31412,96722,299183,925445,3012985, %T A005510 9809425,31952665,104080805,320465225,986713745,3038231465,9355145285, %U A005510 28937578127,89510467490,276877411436,856448448026,2788351903326,9078078610226,29555650383626 %N A005510 a(n) = 1 + a(floor(n/2))*a(ceiling(n/2)) for n > 1, a(1) = 3. %C A005510 All terms are congruent to 3 mod 7. %D A005510 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %p A005510 a:= proc(n) option remember; `if`(n=1, 3, %p A005510 1+(t->a(t)*a(n-t))(iquo(n, 2))) %p A005510 end: %p A005510 seq(a(n), n=1..30); # _Alois P. Heinz_, Jul 04 2019 %Y A005510 Cf. A005468, A005469. %K A005510 nonn,easy %O A005510 1,1 %A A005510 _Colin Mallows_